Issues for Location-Independent Interfaces

Ken Pier and James A. Landay

Technical Report ISTL92-4, Xerox Palo Alto Research Center, December 1992. 

In the future world of ubiquitous computing, interactive devices
ranging in size from pocket to wall will be strewn about the user's
environment.  Display and digitizer surfaces will be merged so that
users appear to interact directly on the display surface using an
electronic stylus or touchscreen.  Within some size range of these
devices, and for some tasks, traditional "widget" style interfaces may
suffice.  However, for devices at the extremes of the size range, such
as the Xerox Liveboard, widget style interfaces break down.  When
interacting directly on a very large display surface, static interface
widgets will be so situated as to be useless, out of reach on the
opposite side of the board, near the ceiling, or near the floor.  In
this paper, we discuss issues and solutions to this problem and
present a prototype example of a location-independent interface.